Nanocomposite anode could power lithium-ion batteries to next level

Conventional lithium ion batteries, such as those widely used in smartphones and laptops, have reached performance limits. An international team of scientists including materials chemist Freddy Kleitz from the Faculty of Chemistry at the University of Vienna in Austria has now developed a new nanostructured anode material for lithium ion batteries that can extend their capacity and lifetime.

Based on a nanocomposite made from a mesoporous mixed-metal oxide in combination with graphene, the material could produce lithium-ion batteries that are more suitable for use in large devices such as electric or hybrid vehicles. The scientists report their research in a paper in Advanced Energy Materials.

With high energy density, extended lifetimes and no memory effect, lithium ion batteries are already the most widespread energy storage devices for portable electronic devices. However, in order to push the batteries to the next level of high performance and durability, and to make them better able to power large devices such as electric vehicles, researchers are looking for new types of active electrode material.

"Nanostructured lithium ion battery materials could provide a good solution," says Kleitz, who, together with Claudio Gerbaldi, leader of the Group for Applied Materials and Electrochemistry at the Politecnico di Torino in Italy, is the paper's main author.

The nanocomposite developed by the two scientists and their teams seriously enhances the electrochemical performance of lithium-ion batteries. "In our test runs, the new electrode material provided significantly improved specific capacity with unprecedented reversible cycling stability over 3000 reversible charge and discharge cycles even at very high current regimes up to 1280 milliamperes," says Kleitz. Today's lithium ion batteries lose their performance after about 1000 charging cycles.

Conventional anodes in current lithium-ion batteries are usually made from a carbon material such as graphite. "Metal oxides have a better battery capacity than graphite, but they are quite instable and less conductive," explains Kleitz.

In their research, Kleitz and his colleagues found a way to combine the best features of metal oxides and carbon. They developed a new family of electrode active materials, based on a mixed-metal oxide and the highly conductive and stabilizing carbon material known as graphene. These materials showed superior characteristics compared to those of most transition metal oxide nanostructures and composites.

Employing a newly designed cooking procedure, the researchers were able to mix copper and nickel homogenously and under a controlled manner to achieve the mixed metal. They then used nanocasting – a method for producing mesoporous materials – to create structured nanoporous mixed-metal-oxide particles. Due to their extensive network of pores, these particles have a very high active reaction area for exchanging lithium ions with the battery's electrolyte. The scientists then applied a spray drying procedure to wrap the mixed-metal-oxide particles in thin graphene layers.

Small batteries that can store as much energy as possible, last as long as possible and are not too expensive to manufacture could advance the use of lithium-ion batteries in large-scale devices. "Compared to existing approaches, our innovative engineering strategy for the new high-performing and long-lasting anode material is simple and efficient. It is a water-based process and therefore environmentally friendly and ready to be applied to industrial level," conclude the study authors.

This story is adapted from material from the University of Vienna, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier. Link to original source.